The invention relates generally to switching devices, such as for machine guarding in industrial applications, and particularly to reteachable switching circuits.
Switching devices are known and are in use for controlling devices in technical installations. Typically, such switching devices are configured to facilitate partial or complete shutdown of electrically driven machines/devices of the technical installation to limit access to the technical installation, at least during certain periods of operation.
One type of switching device is a door switch that includes an actuator-sensor combination for detecting an open state of an access door of the technical installation. Typically, the actuator is coded with a unique identification code that is utilized by the sensor to detect the open state of the access door.
In general, it is desirable to provide switching devices that can be retaught for new actuators in the event that an existing actuator is damaged in the field. However, this may result in maintenance personnel by-passing the switch by using spare actuators taped or otherwise affixed to or near the face of the switch and reteaching the switch for the actuator mounted on the access door. Further, reteaching of the switch for a new actuator may require disruptive steps such as cycling power thereby resulting in substantial downtime of machines/devices of the technical installation.
Accordingly, it would be desirable to provide a robust and secure switching device that can be easily retaught for new actuators without requiring complex or disruptive steps while providing security against reteaching of the switching device for previously used/damaged actuators.